Various encrypted control frameworks have been proposed in conventional works according to the controller type, such as static output feedback [1]}, cooperative control [2]}, [3]}, and model predictive control [4]}, [5]}.
However, this study does not assume a specific type of controller to be encrypted.
A controller is considered as a map from a plant output to the control input to analyze the cryptographic security for as broad a class of encrypted controllers as possible.
